The exposure assessment and intervention project will provide quantitative data on the contact with body burden of neurotoxicants within children having neurological disorders and deficits. The investigators' hypotheses are that: 1) the unique behaviors of these children lead to high exposure to neurotoxicants found in their personal and residential environment, and 2) selected interventions can lead to reductions in exposure measured for neurologically impaired children. Each volunteer child will be selected from families that ate members ofthe community groups associated with this Center's application. The selection will be done in close collaboration with the Clinical Sciences Projects. The goal is to obtain the distribution of personal and micro-environmental exposure of these neurologically impaired children to neurotoxicants; including specific heavy metals, volatile organics, and pesticides that are present and have sources in the local ambient and residential and personal environments of the child. These results will be analyzed over time for each child by collecting exposure measurements at two different times. Once before and once after an intervention, the investigators will assess exposure over time scales coincident with the expression of disease endpoints, and examine reductions in exposure that can occur after completing the intervention and family training. An intervention will apply to the community groups and families, and they should also be valuable to the general public. In addition to the physical and chemical measurements of exposure within their environments and within their bodily fluids, they will be documenting the behavior of these children. The investigators will be using the innovative approaches developed by videotaping and augmented by the core research in this application. Throughout the course of the study, the project will provide data that can be used to augment the neurotoxicants employed by the Basic Biological Sciences Projects.